Eating-inducing compositions for silkworms



United States Patent 3,275,446 EATING-INDUCING COMPOSITIONS FORSILKWORMS Yasuji Hamamura, Keizo Hayashiya, and Kenichi Naito,

Kyoto, Japan, assignors, by direct and mesne assignments, of one-half toYasuji Hamamura, Kyoto, Japan, and one-half to Takeda ChemicalIndustries Ltd., Osaka, Japan, a corporation of Japan No Drawing. FiledNov. 8, 1963, Ser. No. 322,497 Claims priority, application Japan, Mar.6, 1961, 36/7,616, 36/7,617, 36/7,618; Sept. 22, 1961, 36/34,349; Oct.20, 1961, 36/ 37,901; Dec. 1, 1961, 36/ 46,972

11 Claims. (Cl. 99-2) This application is a continuation in part ofapplication Serial No. 176,105 filed February 27, 1962 (and nowabandoned).

The present invention relates to feedstuif for silkworms, and moreparticularly to compositions which induce silkworrns to eat, and to thebiting-stimulating agent, the swallowing-stimulating agent and theattracting agent for silkworms contained therein.

While silk-worms are known to be monophagous in eating nothing butmulberry leaves, no exact reason for this has ever been made clear. Asthe result of extensive studies on the mechanism causing silkworms toselect only mulberry leaves as their natural food, the present inventorshave found that in mulberry leaves there are contained factors such asthe attracting factor which attracts silkworms, the biting factor whichinduces them to bite, the swallowing factor which stimulates them tobite and swallow continuously, that these actors conjointly work onsilkworms for inducing them to eat mulberry leaves, and that these threefactors are indispensable only for the eating of mulberry leaves 'bysilkworms, though the attracting factor can be omitted when thesilkworms are placed on the feed.

The present inventors have discovered that terpenes are the attractingfactor; fl-sitosterol with or without flavonoids is the biting factor;and cellulose powder is the swallowing tactor.

, Further study made it .clear that sufiicientretfect for inducingsilkworms 'to'eat cannot be expected by feeding them a compositioncontaining only fi-sitosterol and cellulose powder, even when silkwormsare placed on the composition, while the two components areirreplaceable substances for the purpose. During further continuance ofthestudy, the present inventors discovered that a sugar and an inorganicphosphate should he present together with the fi-sitosterol andcellulose powder so as to sutficiently induce silkworms to eat. a

Other conditions of the feedstuff, for example, taste, nutritional value[and physical state, are interred, in a strict meaning, to be of merelysecondary significance in regard-to the action of eating, although theyshould .certainly be considered in connection with the insecta-l growth.

The first object of this invention is to provide compositions whichinduce silkworms to eat. The second object lies in stimulating silkwormsin biting. object lies in stimulating silkworms in swallowing. A furtherobject lies in attracting silkworms toward the feedstuif. The firstobject is realized by preparing compositions containing B-sitosterolwith or without flavonoid,

The third Cit a1 3,275,446 Patented Sept. 27, 1966 "ice cellulosepowder, sugar and inorganic phosphate, and a terpene when an attractantis necessary. The second and third objects are realized by incorporatingin the feedstuif for silkworms agents containing B-sitosterol with orwithout flavonoid, and also adding thereto agents containing cellulosepowder, respectively. The said further object is realized -by adding aterpene to the :feedstufi for silkworms. 7

According to this invention, an eating inducing composition iorsilkworms comprises fi-sitosterol, cellulose powder, sugar, an inorganicphosphate and a terpene, it being understood, however, that the terpenecan be omitted when the silkworms are placed on the feed and hence whenno attractant is required. For the practical feeding, addition ofauxiliary factors may come into consideration.

Silkworrns display a remarkable appetite for the compositions of thisinvention, to the same or even a greater extent as compared with thecase when mulberry leaves alone are fed to them. This is asurprisingfinding because to the best of our knowledge the finding hasoverthrown the previously established theory in sericulture dependentsolely =on mulberry leaves.

Table I shows the result of an attracting test of silk- Worms which iscarried out as follows:

Six small circles along the circumference of a round filter paper aredrawn in equal intervals and the paper is set in a dish (diameter: 8.5cm.). A certain amount of each solution of the samples is absorbed on0.25 gram cellulose powder, the solvent is evaporated in the air, andthen water is sprayed on it; on the other hand, the same amount ofcellulose powder containing a small amount of water is prepared ascontrol. "I hese cellulose powders are divided into three portionsrespectively and the thus prepared control cellulose powders and samplesare put on the six circles alternately. Thirty hatchedlarvae are placedon the :center of the filter paper. After leaving the dish standing at24 -C. for one hour, the number of larvae gathered to each powder andwandering at the intermediate space are counted.

TABLE I 7 Concentration 9% 1 3 5 ISCISC Terpinyl acetate- Linalylacetate Home I so on. S, Cand I mean sample, contorl andintermediatespace, respectively.

Table I I shows the result of the test of biting action of silkworms onagar thread which is softened with a small amount of water and sprayedwith a 5 percent ethereal solution of fi-sitosterol.

TABLE II 13-sitosterol (triple spray) l Control In the test larvae wereemployed, and denotes that all larvae iblt the agar thread and denotesthat none of the =larvae bit the agar thread.

In the composition of this invention the sugar and inorganic phosphateappear to be primarily related to the taste of the food and to theswallowing act-ion of the silkworms, respectively.

The sugar employed in this invention may be, for example, surcrose,fructose, glucose, etc. The flavonoid may be .quercetin, morin, rutin,isoquercitrin, etc., and the terpene may he oitral, linalyl acetate,linalol, terpinyl acetate, etc. The inorganic phosphate employed in thisinvention, is for example, potassium dihydrogen phosphate, dipotassiumhydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogenphosphate, calcium phosphate, etc. Among these inorganic phosphates,potassium dihydrogen phosphate has been found to be preferred.

The cellulose powder employed in this invention is, in most cases,preferably coated with silica.

The respective quantities of components of compositions of thisinvention may be varied depending on various conditions such as inst-aror the state of the silkworms and the kind or quantity of the othercomponents in the artificial feed. Generally the ,B-sitosterol ispresent in the amount of about 0.1 to 1 percent; the cellulose powder 20to '60 percent; the sugar 1 to 10 percent; the inorganic phosphate 0.2to 2 percent; the terpene in a trace amount (0.001 to 0.01 percent), andthe flavonoid 0.1 to 0.3 percent. (All percentages are weight/weightunless otherwise described, based on the total weight of the artificialfeed.) 'In some cases, the amount of cellulose powder may 'be more than20 to 60 percent, because cellulose powder also serves the roll of acarrier.

In most cases the compositions of this invention may be utilized inpowdery form for a practical application by mixing with variouscomponents which are necessary for the growth of silkworms, e.g.protein, starch, vitamins, minerals, etc., to obtain the artificial feedwith which silkworms can be fed without any mulberry leaves to producenormal cocoons. The compositions may also [be used in jelly or pasteform with agar or starch.

The further addition of in-ositol may result in bringing about apreferred effect in many cases.

The "following non-limitative examples are given for the purpose ofillustrating embodiments of this invention, it being understood thatmodifications and variations of the compositions herein described in thespecification and claims are included in the scope of this invention.

The components mentioned above are thoroughly admixed and added to 2000to 3000 parts by volume of a 2 percent agar solution or to 2000 to 3000parts by volume bf a 10 percent starch paste.

Percent S-Sit-osterol 0.1 to 1 Cellulose powder 20 to 60 Sugar 1 to 10Inorganic phosphate 0.2 to 2, fI'erpene 0.001 to 0.01 Flavonoi'd 0.1 to0.3 i

4. A composition for inducing silkworms to eat comprising the followingingredients in approximately the following relative proportions based onthe total weight of the composition: Parts by weight Citral 0.1fl-Sitosterol 5 Isoquercitrin or morin A 3 Cellulose powder .700 Sucrose30 Inositol 5 K' HPO 10 j 5. A composition according to claim 3,.wherein the cellulose powder is coated with silica.

6. -A composition according to claim 3, wherein. the sugar is selectedfrom the group consisting of fiructose, glucose and sucrose.

7. A composition according to claim 3, wherein the inorganic phosphateis K H PO 8. A composition according to claim. 3,-wherein the terpeneis: selected from the group consisting of terpinyl. acetate, linalylacetate, linalol and citral.

9. A composition according to claim. 3, wherein1 the flavonoid isselected from the group consisting of isoquerr citrin and morin. I

10. A composition for inducing silkworms to eat comprising,B-sitosterol, cellulose powder, a sugar, an in organic phosphate, aflavonoid and inositol.

-1l. A composition for inducing silkworms to eat com-- prisingfl-sitosterol, cellulose powder, a ,sugar, an inorganic phosphate, aterpene, a flavonoid and inositol.

References Cited by the Examiner UNITED STATES PATENTS 2/ 1908 Kennedy71.-23- 2/19-35' Naruse 99-2' OTHER REFERENCES A. LOUIS MONACELL,Primary Examiner.-

D. I. DONOVAN. Assistant Examiner.

1. A COMPOSITION FOR INDUCING SILKWORMS TO EAT COMPRISING B-SITOSTEROL,CELLULOSE POWDER, A SUGAR, AN INORGANIC PHOSPHATE AND A FLAVONOID.